The invention relates to a blanket, in particular a quilt.
Blankets, particularly quilts, should protect the human body. They create a zone between the body and the surrounding air which impedes an exchange of heat between the body and the surroundings and thereby reduces the radiation of heat from the human body, thereby preventing undercooling of the body.
Depending on the ambient temperature, it may be desired that more or less of the heat produced by the human body escape through the blanket. If the ambient temperature is low and the heat gradient is thus relatively high, as for example in the winter, then the blanket should retain as much of the heat produced by the body as possible. If, on the other hand, the ambient temperature is relatively high, as for example in the summer, then it may even be desired that as much heat as possible be carried away from the human body.
As a rule, the retention of heat is essentially achieved by providing an immovable air volume above the human body, i.e. the effect is for the most part achieved by a stationary air cushion, Whereby use is made of the fact that air has a low coefficient of thermal conduction.
This means that a blanket, in particular a quilt, should allow a transmission of heat that is inversely proportional to the temperature drop. This is not possible with conventional blankets.
It was therefore proposed to use different blankets in the summer than in the winter or fall and spring which is why one speaks of so-called "summer blankets", "winter blankets" and "fall blankets".
"Winter blankets" and "fall blankets" are designed in such a way that if possible there are no thermal bridges. Thus, instead of normal quilting seams, webs are used, which ensure that the top sheet is the same distance, if possible, from the bottom sheet in the area of the stitching as in the area between the stitching. Fall blankets and in particular winter blankets are also fuller or thicker in order to hold as large an air volume as possible. In the summer these blankets are too warm, i.e. heat builds up under the blanket since the heat produced by the person is not carried away due to the low heat conductivity and the relatively low temperature drop in the summer.
"Summer blankets" are very light, and can also have quilting seams forming otherwise undesired thermal bridges. These so-called thermal bridges allow the heat to pass through very easily. If necessary, a summer blanket should also be able to absorb or let through the perspiration given off by the human body.
It has also been proposed to design a quilt as a blanket system such that several individual blankets can be combined into one overall blanket to form one blanket which is thicker in relation to the individual blankets. However, this blanket is then also correspondingly heavier.
In both known proposals, the use of two blankets is provided, whereby the second blanket must be stored when it is not being used.
A blanket with a filling is known from GB-A-2 159 050, its covering consisting of two cover sheets of different sizes which are joined together by means of stitching in the form of stripes such that when the blanket is flat the one top sheet lies flat whereas the other top sheet is curved over it. The quilting seams are farther removed from one another on the surface of the curved cover sheet than on the cover sheet that lies flat.
If the smaller cover sheet is on the bottom and lies on the person, then large thermal bridges form in the area of the stitching, particularly through the bulging of the entire blanket over the person. If the blanket is turned around so that the larger cover sheet is on the bottom and lies on the person, then adjacent parts of the larger cover sheet lie on top of one another in the area of the stitching and the thermal bridge otherwise present in the area of the stitching is substantially closed over the entire surface of the blanket.
However, the user must always ensure that the right side of the blanket is placed on the bottom. He can no longer turn the blanket around, especially when sleeping. If the blanket is provided with a covering, then it is very difficult to find the right side. The manufacture of such blankets is also relatively complicated and thus expensive.
A blanket is also known from German A-3 723 926(not pre-published), which illustrates a type of blanket with tubes passing through over its entire length. Alternately small and large tubes are provided. The large tubes are filled with filling material, whereas the small tubes form a tunnel for a gathering tape. If this gathering tape is gathered, then the size of the blanket can be adapted in one dimension, namely along tubes, to the desired requirements, such as size of the bed, size of the covering, and the like or to the desired function. Due to the missing filling material, there is a very large thermal bridge in the area of the smaller tubes forming the tunnels which does not become smaller even when gathering the blanket. Although the blanket produces a smaller heat emission in the area of the filled tubes because of the geometry when it is gathered, this blanket is not suitable for retaining more heat in the winter than in the summer because of the tunnels that are empty of filling material.